High-energy particles have been used to create tracks and perforations in films and foils. The films and foils may be subjected to etchants which act on the damaged track area of the films and foils to make or adjust the size of the track and perforations. Such films and foils have many applications including, without limitation, filters and molecular sieves.
The use of high-energy particles to produce tracks in substrates is disclosed in several references. By way of example, U.S. Pat. No. 3,303,085, to P. E. Price et al., entitled MOLECULAR SIEVES AND METHODS FOR PRODUCING SAME, discloses the use of charged particles to produce articles having openings or apertures.
U.S. Pat. No. 3,677,844, to R. L. Fleischer et al., entitled PROCESS FOR MAKING AN ELASTIC STRETCHY SHEET CONTAINING APERTURES HAVING A DIAMETER OF AT LEAST FIVE ANGSTROMS AND BEING SUITABLE AS A MOLECULAR SIEVE, discloses the use of a combined etchable polymer and unetchable polymer, subjected to high-energy particles, which high-energy particles form substantially straight tracks of damaged copolymer. The aperture containing polymer includes properties usually associated with the nonetchable polymer to which it is bound.
U.S. Pat. No. 3,852,134, to C. P. Bean, entitled METHOD FOR FORMING SELECTIVELY PERFORATE BODIES, discloses methods for forming a selectively perforate membrane suitable for high-resolution screen printing by radiating a sheet of synthetic resin with heavy fission fragments.
In an article entitled "Characteristics of Submicron Pores Obtained by Chemical Etching of Nuclear Tracks and Polycarbonate Film," G. Guillot and F. Rondelez disclose a method and apparatus for producing pore perforations in solid material in sheet form with an isochronous cyclotron. The article appeared in the Journal of Applied Physics, Vol. 52, No. 12, December 1981, pages 7164-947.
M. Matthes, W. Pfosterf and N. Seidal, report in an article entitled "Eine Bestrahlungsanlage Fur Polienmaterial," an apparatus for producing perforations in solid material in sheet form with an accelerato. The apparatus features a tank or high vacuum chamber adapted to contain a handler. The handler is adapted for handling a material for treatment by the accelerator and in particular comprises a spool of nonbombarded material, a mandrel for winding the material after it has been bombarded and guide rollers. The article appeared in the publication Gemeinsamer Jahresbericht, June 1984.
In a review article entitled "Production and Use of Nuclear Tracks: Imprinting Structure on Solids," Fischer and Spohr discuss apparatus and methods for producing perforations in solid material in sheet form with accelerators. The device and methods of Fischer and Spohr feature various handlers for handling material in a continuous process. The article appeared in the publication Reviews of Modern Physics, Vol. 55, No. 4, October 1983.
In a series of articles, Flerov et al. disclose devices and methods for forming perforations in solid materials in sheet form with accelerators. The articles are entitled, "Practical Applications of Heavy Ion Beams," appearing in the Sov. Phys. USP., Vol. 17, No. 5 (March-April 1975), pages 783-793; and "On the Technology of Manufacturing Microfilters with Higher Specific Efficiency," appearing in Atomnaya Energlya, USSR (1983) Vol. 53, No. 3 p. 181 et sequence.
E. U. Apel discloses in an article, entitled "Measurements of the Diameter of Selectively Etchable Tracks Produced in Polymer by Heavy Ions," methods and apparatus for producing perforations in solid materials. The article appeared in Nuclear Tracks, Vol. 6, No.2-3 pp. 115-118, 1982.
U.S. Pat. No. 4,956,219, to Legras et al., entitled METHOD OF PRODUCING PERFORATIONS IN A SOLID MATERIAL IN SHEET FORM, AN IRRADIATION DEVICE FOR WORKING THE METHOD, AND THE RESULTING PERFORATED MATERIAL, discloses a method of, and apparatus for, producing perforations in solid material in sheet form with a isochronous cyclotron. An isochronous cyclotron is an apparatus for producing high-energy charged particles. The device and methods of the Legras et al. reference feature a high-vacuum chamber through which particles pass, a tank adapted to contain a handler, and a diaphragm separating the chamber from the tank. The handler is adapted for handling a material for treatment by the isochronous cyclotron. In particular, the handler comprises a spool of nonbombarded material, a mandrel for winding the strip after it has been bombarded, and guide rollers and drive means for advancing the strip of material.
European Patent Application No. 83305268.1, Publication No. 0109147, to Varian Associates, Inc., entitled CHARGED PARTICLE BEAM LITHOGRAPHY MACHINE INCORPORATING LOCALIZED VACUUM ENVELOPE, teaches the use of charged particle beam lithography with localized vacuum processing.
Devices for performing bombardment of materials with high-energy particles are well known and have applications in research and industry. All devices for accelerating charged particles employ an electric field. Accelerators may differ in the way the electric field is produced and the manner in which the field acts on the particles. The high-energy charged particles produced by each accelerating type are identical for a given ion and energy.
Accelerators are generally classified as falling within two types--electrostatic accelerators and high frequency accelerators. Van de Graaf accelerators and Tandem accelerators are examples of electrostatic accelerators. Electrostatic accelerators are generally capable of producing energies of between 10 KeV and 10 MeV.
High frequency accelerators are characterized by an ion beam which encounters the same acceleration voltage several times. High frequency accelerators are generally classified into two sub-types--linear accelerators and cyclic accelerators. Linear accelerators employ a linear array of gap electrodes to accelerate a successive passage of ions. A Wideroe and Alvarez accelerator is an example of a linear accelerator.
Cyclic accelerators employ magnetic deflection for recycling particles through an accelerating gap subject to high frequency voltage. Cyclotrons and synchrotrons are examples of cyclic accelerators. Cyclic accelerators are capable of producing energies between 10 MeV and a few GeV, but may attain even higher energies.
Devices for performing bombardment with high-energy charged particles are expensive to operate. Efficient processing of materials with high-energy charged particles is therefore necessary.